1. Field of the Invention
The present invention relates to an electric motor preferably used in a motor-driven power steering apparatus or the like.
2. Description of the Related Art
A motor-driven power steering apparatus for a vehicle is structured, as described in Japanese Patent Application Laid-Open No. H9-84300 (patent document 1), such that an assist shaft of a steering apparatus is connected to a rotation shaft of an electric motor, and a rotation force of the electric motor is transmitted to the steering apparatus, thereby assisting steering force applied to a steering shaft by a driver.
A conventional electric motor is structured, as described in Japanese Patent No. 3207177 (patent document 2) such that a pigtail firmly fixed to a brush is connected to a conductor insert molded integrally with a brush holder base at one end thereof. An electric power is fed from a connector which is connected to a lead wire extending to an outer portion from another end of the conductor and is held by an outer terminal.
In a conventional electric motor, in order to reduce the number of connecting portions between outer terminals, a structure in which a terminal insertion hole, to which a terminal connected to a brush is inserted, is provided in a feed connector integrally formed with a brush holder, and an opposing connector is connected to the terminal inserted into the terminal insertion hole. A come-off or unintentional disassembly preventing means is supplied for preventing the terminal from coming off from the terminal insertion hole on the basis of a pressing force applied by the opposing connector. A tongue-like prevention hook is provided in the brush holder, the terminal elastically deforms the come-off or unintentional disassembly prevention hook during a step of being inserted into the terminal insertion hole, and the come-off or unintentional disassembly prevention hook restoring after inserting the terminal to the terminal insertion hole is abutted against a base end portion of the terminal. However, the tongue-like come-off or unintentional disassembly prevention hook provided in the brush holder tends to be cracked and broken, and the productivity and a reliability of the electric motor tend to be damaged.
Further, as a drag-in preventing means for preventing the terminal from being dragged in the terminal insertion hole by a pulling force applied by the opposing connector when canceling the connection of the opposing connector after connecting the opposing connector to the terminal inserted into the terminal insertion hole, a structure in which a pigtail connection portion welded to the terminal is employed. The pigtail connection portion abuts against an opening peripheral edge of the terminal insertion hole so as to prevent the terminal from being dragged in. However, in the case where the welding position of the pigtail to the terminal is displaced even a little amount, the terminal may tend to move in a direction of dragging in.